Distillate fuels



United States Patent 0.

3,269,809 DISTTLLATE FUELS John E. Engelhart, Westfield, Leonard Berkowitz, Elizabeth, and Barrel] W. Brownawell, Scotch Plains, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Apr. 17, 1963, Ser. No. 273,577

7 Claims. (Cl. 4462) This invention concerns an improved petroleum distillate fuel and more particularly relates to a middle distillate fuel containing multifunctional additives.

Terpolymers consisting of alkyl chloropropyleneoxy mixed esters, vinyl acetate, and a tallow fumarate, have been used to stabilize middle distillate fuels. It has now been found that, by replacing the tallow fumarate with a normal C to C a kyl fumarate or mixtures thereof, the resulting terpolymer acts as an effective pour point depressant in middle distillate fuels. Moreover, the C alkyl furnarate terpolymer used in combination with a oopolymer of ethylene and vinyl acetate acts to improve the filterability of the fuels.

The terpolymer of this invention consists of from 15 to 75 wt. percent of a vinyl ester of a short chain fatty acid, for example, vinyl acetate, from to 80 wt. percent of a normal C to C alkyl fumarate, and from 1 to wt. percent of a long chain saturated aliphatic alcohol-chloropropyleneoxy mixed ester of an unsaturated conjugated dibasic acid, said acid having from 4 to 5 carbon atoms per molecule. These esters, referred to hereinafter as alkyl chloropropyleneoxy mixed esters, are thought to have the following general formula:

0 O RO( 3C:C("30(CH2CH-O)H r i R 011 01 where R is an alkyl group containing from about 4 to 24 carbon atoms; R and R" are constituents selected from the class consisting of hydrogen atoms and methyl groups, at least one such constituent being a hydrogen atom; and 11 may vary from 1 to 3 or more, depending upon the quantity of epichlorohydrin employed in preparing the esters.

The alkyl-chloropropyleneoxy mixed esters employed in preparing the copolymers of the invention may be readily obtained by first reacting an unsaturated conjugated dibasic acid with a long chain saturated aliphatic alcohol to form a half ester and then reacting this product with epichlorohydrin in the presence of an acidic (electron acceptor) catalyst to produce the mixed ester. The addition of epichlorohydrin to the half ester may also be r catalyzed by basic groups, e.g. CH O*, OH. Suitable unsaturated conjugated dibasic acids for preparing the mixed esters in this manner include maleic acid, fumaric acid, citraconic acid, mesaconic acid, and mixtures of such acids. The butenedioic acids, i.e., maleic and fumaric acids and mixtures of the two, are preferred acids. It is preferable to employ the acids in the form of their anhydrides, in which case the half ester can be produced by merely heating one mole of the anhydride with one mole of the long chain saturated aliphatic alcohol at a temperature of about 70 to 120 C. for about thirty to about forty-five minutes. Other well-known methods for the production of half esters of dibasic acids may also be employed.

The long chain saturated aliphatic alcohols reacted with the dibasic acids or acid anhydrides to produce half esters may contain from about 8 to 24 carbon atoms per molecule, those containing from about 8 to about 18 carbon atoms being preferred. Straight chain primary alcohols such as dodecyl, cetyl, eicosyl and docosyl are preferred, but it is permissible to use branched alcohols such as 2- ethylhexanol-l and C oxo alcohols, secondary alcohols 'ice such as 2-decan0l and mixtures of straight and branchedchain alcohols if desired.-

Commercially marketed mixtures of alcohols consisting essentially of saturated aliphatic alcohols having the requisite chain length may also be used. One such preferred mixture prepared by the hydrogenation of coconut oil is sold under the trade name Lorol and is comprised of saturated aliphatic alcohols containing from 10 to 18 carbon atoms per molecule. This mixture consists chiefly of lauryl alcohol having 12 carbon atoms per molecule and has the following approximate composition.

Number of carbon atoms: Weight percen Lorol is thus a commercial mixture of saturated aliphatic alcohols containing from 10 to 18 carbon atoms per molecule and having an average chain length of 12-14.

The C oxo alcohol effective for use in preparing the additives of the invention is normally obtained by the oxonation and hydrogenation of a C copolymer of propylene and butene. The copolymer itself is in reality a mixture of isomers and the resultant oxo alcohol may have the following general analysis:

STRUCTURE OF C OXO ALCOHOL PREPARED FROM C -C COPOLYMER HEPTENES Higher molecular Weight oxo alcohols may also be used in preparing the additives of the invention. These higher molecular weight alcohols are believed to have compositions generally analogous to that specified above, chain lengths and degree of branching depending upon the type of olefins used in preparing the copolymers. The process used for the manufacture of 0x0 alcohols is now well known in the art and need not be further described.

The half esters prepared by reacting the dibasic acid and alcohol are in turn reacted with epichlorohydrin in the presence of from about 0.05 to 5.0 percent by weight of an acidic (electron acceptor) catalyst such as boron trifluoride, boron trifiuoride etherate, aluminum trichloride, aluminum tribromide or the like or a basic catalyst such as NaOC-H or NaOH. The reaction is carried out by slowly adding the epichlorohydrin to the half ester mixed with catalyst over approximately a one to two hour period. The temperature at which the addition is carried out may range between about 100 C. and 180 C. The reactants are held at this temperature from about 4 hours to about 24 hours or longer. Depending upon the number of chlorine atoms desired per molecule of mixed ester, the esterzepichlorohydrin ratio may range between about 1:1 to about 1:4. Under these conditions the addition of the epichlorohydrin molecule to the half ester takes place through the epoxy group and the chlorine atom of the epichlorohydrin is unaffected.

The polymerization of the three above-identified ingredients may be carried out in a solution of benzene or other suitable organic solvent at a temperature in the range of from about 60 to about 250 F. and may be promoted by gamma radiation or by the use of a peroxide type catalyst such as benzoyl peroxide. It is desirable to exclude oxygen during the polymerization by the use of a blanket of inert gas such as nitrogen or carbon dioxide. The polymerization time may vary from about 1 to 36 hours.

The resulting terpolymer may have a molecular Weight of from about 3000 to 100,000 or higher. Molecular weights of from about 6000 to 30,000 are particularly preferred.

To lower the pour point of a middle distillate fuel the above-described terpolymer is incorporated in said fuel in a concentration of from 0.0025 wt. percent to 2.0 wt. percent and preferably from 0.01 wt. percent to 0.1 wt. percent.

The petroleum distillate fuels in which the terpolymers of this invention are employed consist of a major proportion, at least 95%, of liquid hydrocarbons boiling at temperatures of between about 70 F. and about 750 F. The terpolymers are particularly effective in fuels boiling in the range of from about 250 F. to 750 F.

Example I Tests were run in order to determine the efficacy of the additive as a pour point depressant. The terpolymer consisting of 68.14 wt. percent of normal C alkyl fumarate, 15.2 Wt. percent vinyl acetate, and 16.4 wt. percent of C oxo chloropropyleneoxymaleate was added to fuels of the following description.

The pour point of each fuel without additive and the pour points of the fuel with various concentrations of the C alkyl fumarate terpolymer were determined in accordance with a standard ASTM test.

The data in Table I demonstrate the eflicacy of the invention.

TABLE I Weight Percent 012 Alkyl Fumarate Fuel 1, Fuel 2, Fuel 3,

Terpolymer Added F. F.

It is seen that the terpolymer was effective in reducing the pour point of each of the base fuels. If a tallow (C fumarate is substituted for the C to C alkyl fumarate employed in the polymer, the resulting terpolymer is not an effective pour point depressant. The instant terpolymers are as effective in dispersing sediment as are the prior art terpolymers containing the tallow fumarate. Moreover, the alkyl fumarate must be a normal alkyl fumarate. The use of the shorter chain fumarates, for example, C to C as well as the use of the longer chain fumarates, for example, C and above, result in a terpolymer which is not effective as a pour point depressant.

In addition to being an effective pour point depressant, the terpolymers of this invention may be used in combination with copolymers of ethylene and up to about 50% by Weight of an olefinically unsaturated aliphatic monomer containing from about 3 to 5 carbon atoms per molecule. In general, these monomers may comprise vinyl acetate, vinyl propionate, methyl methacrylate, allyl ethyl ether, divinyl ether, and the like. These copolymers are described in British Patent 915,890.

The additive combination is employed in a range of from about 0.01 wt. percent to 2.0 wt. percent in a middle distillate fuel in order to enhance the filterability. The combination consists of the copolymer and terpolymer employed in a ratio on a weight basis of from 2:1 to 8:1 parts of copolymer per part of terpolymer.

Example 2 The above-described additive combination was tested in Fuel 1 described in Example 1. The copolymer employed consisted of Wt. percent ethylene and 25 wt. percent vinyl acetate. The terpolymer employed was the same as that used and described in Example 1. Filtration tests were performed utilizing a Buchner funnel equipped with whatman No. 1 filter paper, vacuum apparatus and refrigeration apparatus suflicient to lower the temperature of the fuel sample to 20 F. 450 grams of the fuel to be tested Were added to the funnel and subjected to a vacuum of 25 inches of mercury. As is seen in Table II, 37% of the base fuel filtered through the system in 30 minutes at a filter rate of 5 grams per minute. By adding 0.03 Wt. percent of the copolymer of ethylene and vinyl acetate filterability of the fuel increased to 63% at a rate of 10 grams per minute. By replacing a portion of the copolymer with only 0.005 wt. percent of the C fumarate terpolymer, 96% of the fuel filtered through the paper in 30 minutes with a filter rate of 12.9 grams It is seen from the above data that a small amount of the terpolymers of this invention used in combination with an ethylene-vinyl acetate copolymer greatly increases the filterability of a middle distillate fuel. Thus, it is seen that adding this combination to a middle distillate fuel yields a fuel which is not likely to clog filters, thus insuring efiicient and continuous operation in the field.

What is claimed is:

1. A petroleum distillate fuel comprising a major proportion of a petroleum distillate fuel boiling in the range of between 70 F. and about 750 F. and a minor amount sufficient to decrease the pour point of said fuel of a terpolymer of from 75 to 15 Wt. percent of a vinyl ester of a short chain fatty acid from 20 to of a normal C to C alkyl fumarate and from 1 to 30% of a long chain saturated aliphatic alcohol-chloropropyleneoxy mixed ester of an unsaturated conjugated dibasic acid, said acid having from 4 to 5 carbon atoms per molecule; said terpolymer having a molecular weight of between 3,000 and about 100,000.

2. A fuel according to claim 1 wherein said vinyl ester is vinyl acetate.

3. A fuel according to claim 1 wherein said fumarateis a mixed C to C fumarate.

4. A fuel according to claim 1 wherein said minor amount is from 0.0025 wt. percent to 2.0 wt. percent.

5. A fuel according to claim 1 wherein said fumarate is dodecyl fumarate.

6. A petroleum distillate fuel comprising a major proportion of a petroleum distillate fuel boiling in the range of from 70 F. to 750 F. and a minor amount suflicient to enhance the filterability of said fuel of (A) a terpolymer of from 15 to 75 wt. percent of a vinyl ester of a short chain fatty acid, from to 80% of a normal C to C alkyl fumarate and from 1 to of along chain saturated aliphatic alcoholchloropropyleneoxy mixed ester of an unsaturated conjugated dibasic acid, said acid having from 4 to 6 5 carbon atoms per molecule; said terpolymer having a molecular weight of between 3000 and 100,000, and (B) a copolymer of from Wt. percent to Wt. percent ethylene and 10 Wt. percent to 50 wt. percent of an olefinically unsaturated aliphatic monomer containing from about 3 to 5 carbon atoms per molecule; the ratio of copolymer to terpolymer being from 2:1 to 8:1 on a weight basis. 7. A fuel according to claim 6 wherein the combination of additives is present in the fuel in an amount of from 0.01 wt. percent to 2.0 wt. percent.

References Cited by the Examiner UNITED STATES PATENTS 3,093,623 6/1963 Ilnyckyj 44-70 3,136,743 6/1964 Conway et a1. 260-78.5 3,160,484 12/1964 Siegel 44-62 DANIEL E. WYMAN, Primary Examiner.

Y. M. HARRIS, Assistant Examiner. 

1. A PETROLEUM DISTILLATE FUEL COMPRISING A MAJOR PROPORTION OF A PETROLEUM DISTILLATE FUEL BOILING IN THE RANGE OF BETWEEN 70*F. AND ABOUT 750*F. AND A MINOR AMOUNT SUFFICIENT TO DECREASE THE POUR POINT OF SAID FUEL OF A TERPOLYMER OF FROM 75 TO 15 WT. PERCENT OF A VINYL ESTER OF A SHORT CHAIN FATTY ACID FROM 20 TO 80% OF A NORMAL C12 TO C14 ALKYL FUMARATE AND FROM 1 TO 30% OF A LONG CHAIN SATURATED ALIPHATIC ALCOHOL-CHLOROPROPYLENEOXY MIXED ESTER OF UNSATURATED CONJUGATED DIBASIC ACID, SAID ACID HAVING FROM 4 TO 5 CARBON ATOMS PER MOLECULE; SAID TERPOLYMER HAVING A MOLECULAR WEIGHT OF BETWEEN 3,000 AND ABOUT 100,000. 